<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
        <title>Document</title>
        <style>
            * {
                margin: 0;
                padding: 0;
                list-style: none;
            }
            ul {
                width: 1000px;
                margin: 100px auto;
            }
            li {
                height: 30px;
                width: var(--i);
                background-color: red;
                margin-bottom: 4px;
            }
        </style>
    </head>
    <body>
        <ul>
            <li style="--i: 10%"></li>
            <li style="--i: 20%"></li>
            <li style="--i: 33%"></li>
        </ul>
    </body>
</html>
